BRISBANE - Despite reaching a legal settlement with federal attorneys in January, environmentalists fear that the landmark plan designed to preserve San Bruno Mountain is as endangered as the species it was intended to protect.

The ongoing frustration among environmentalists, coupled with efforts by state and local officials to amend the San Bruno Mountain Habitat Conservation Plan, reveals that the two sides remain opposed after nearly 20 years of negotiations.

San Mateo County Senior Planner Sam Herzberg, one of the habitat administrators, says that while changes are needed, the plan is working.

"At one point, all of San Bruno Mountain was proposed for development. The HCP has curtailed a lot of development," said Herzberg.

But Philip Batchelder of the environmental organization San Bruno Mountain Watch says the plan is "grossly under-funded" and failing. And to make matters worse, he alleges that the plan's administrators are hoping to add another butterfly to its endangered species list.

Adding the callippe silverspot butterfly to the conservation plan would allow developers to kill the endangered species as long as they provide habitat for it to survive elsewhere on the mountain.

In the fall, the U.S. Fish and Wildlife Service approved a grant that would allow the county and its environmental consultants $100,000 to amend the plan. Changes to the plan would include not only adding the silverspot but would create something more "comprehen- sive," according to Herzberg.

Batchelder, however, believes that the amendment would be a death sentence for the silverspot.

"This species is barely hanging on. It can't afford to be compromised. We're fundamentally opposed to adding another species to what we consider to be a failing plan," he said.

Environmentalists such as Batchelder fear that the amendment would open the door for Brookfield Developers to add more homes to the mountain's northeast ridge. The developer is currently prohibited from expanding because parcels along this ridge are habitat for the federally endangered silverspot. The only way for the housing project to expand would be adding the butterfly to the Habitat Conservation Plan.

"The plan sounds nice," said David Schooley, a member of San Bruno Mountain Watch. "But what it means is that a developer can kill that habitat as long as they are planning to recreate that habitat. Exactly what does that mean?"

Herzberg argues that environ- mentalists want the .Habitat Conservation Plan to be black and white. But this was never the intent of the agreement.

"The Habitat is nothing if not gray. It's a compromise," he said. The compromise was the first of its kind internationally, according to Herzberg. Since the conservation plan was crafted in 1986, more than 300 similar plans have followed,

"Has the plan done everything that environmentalists want? You know what, most of the mountain is open space Herzberg said.

The mission blue butterfly was the original endangered species listed on the conservation plan, which allowed developers to build on its habitat. But when the U.S. Fish and Wildlife proposed adding the silverspot to the plan, San Bruno Mountain Watch sued. The organization filed its lawsuit on July 11, 2000, charging the federal agency with deliberately jeopardizing an endangered species

After a lengthy legal battle, U.S. Fish and Wildlife settled earlier this year. The agency agreed to pay San Bruno Mountain Watch $130,000, which the organization says will go towards paying legal fees.

In addition to the payment, Fish and Wildlife agreed to conduct formal biological studies pertaining to endangered plant and animal species on the mountain. The agency also agreed to investigate the effec- tiveness of the San Bruno Mountain Habitat Conservation Plan and the adequacy of its funding.

While the settlement was a victory for San Bruno Mountain Watch, the organization continues to cast doubt on Fish and Wildlife following through with its promise. Meanwhile, the mountain's stewards will wait and see if the amendment goes through.

"We've settled, but we're not feeling too settled," said Batchelder. "We were willing to settle with the service, but we still have to see if they can put together a good plan."